Over the centuries, clock designs have on occasion been embellished with kinetic actions to add interest that were not involved with the function of timekeeping. Also, functional actions such as pendulums, balances and escapements were often featured for interest. Pendulums took such forms as cupids on a swing or Villard's flying ball clock pendulum (invented c. 1240). Also very interesting kinetic motion type mechanisms were the rolling ball balance-escapement clocks invented by the Frenchman Grollier in the seventeenth century and further developed by Congreve, the Englishman.
Then, of course, the entire timekeeping mechanisms were often displayed in versions called skeleton clocks.
Timekeeping functions of the periodic nature such as chime striking were sometimes featured in kinetic motions such as a mechanical man swinging a mallet to strike the chimes. These actions were still of a timekeeping nature as they acted each quarter hour, or half hour or hour. The classic of this chime striking action is of course the cuckoo.
Clock mechanisms have traditionally been powered by gravity, wound springs and electric motors. These power mechanisms were kept separate between the continuous timekeeping functions and the periodic functions. This is mainly because the continuous timekeeping movements were very slow, ranging from the second hand at 1 RPM, minute hand at 1/60 RPM, and the hour hand at 1/720 RPM.
The striking functions, however, are periodic, not continuous and run about 20 to 60 RPM. So, separate power sources are employed. As an example, cuckoo clocks use one weight or key wound spring for the continuous mechanism that involves the hour hand, the minute hand, and the pendulum; then they make use of a separate weight or key wound spring for the periodic cuckoo mechanism and the bellows for the cuckoo call.